U.S. patent number 9,721,448 [Application Number 14/569,889] was granted by the patent office on 2017-08-01 for wireless communication systems for underground pipe inspection.
This patent grant is currently assigned to King Fahd University of Petroleum and Minerals, Massachusetts Institute of Technology. The grantee listed for this patent is Massachusetts Institute of Technology. Invention is credited to Rached Ben-Mansour, Samir Mekid, Dalei Wu, Kamal Youcef-Toumi.
United States Patent |
9,721,448 |
Wu , et al. |
August 1, 2017 |
Wireless communication systems for underground pipe inspection
Abstract
Wireless communication system for underground pipeline
inspection. The system includes a plurality of sensor nodes moved
by robots within the pipeline and each sensor node includes a radio
transceiver. A plurality of spaced apart, above ground relay nodes
are deployed along the pipeline, each relay node including a radio
transceiver for communication with the sensor nodes. A remote
monitoring center is provided in communication with the relay
nodes, whereby a leak detected by a sensor node is communicated to
the remote monitoring center. Each sensor node may further include
a microcontroller, an accelerometer and a timer.
Inventors: |
Wu; Dalei (Cambridge, MA),
Youcef-Toumi; Kamal (Cambridge, MA), Mekid; Samir
(Dharhan, SA), Ben-Mansour; Rached (Dhahran,
SA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Massachusetts Institute of Technology |
Cambridge |
MA |
US |
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Assignee: |
Massachusetts Institute of
Technology (Cambridge, MA)
King Fahd University of Petroleum and Minerals (Dhahran,
SA)
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Family
ID: |
53400627 |
Appl.
No.: |
14/569,889 |
Filed: |
December 15, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150179044 A1 |
Jun 25, 2015 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61918791 |
Dec 20, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G08B
21/20 (20130101); H04W 36/18 (20130101); G01M
3/18 (20130101); H04W 52/0203 (20130101); G01M
3/243 (20130101); H04W 84/12 (20130101); Y02D
30/70 (20200801); Y02D 70/142 (20180101); Y02D
70/1226 (20180101); Y02D 70/1224 (20180101); Y02D
70/146 (20180101); Y02D 70/1262 (20180101); Y02D
70/164 (20180101); Y02D 70/22 (20180101) |
Current International
Class: |
G08C
17/00 (20060101); G01M 3/18 (20060101); G01M
3/24 (20060101); H04W 36/18 (20090101); G08B
21/20 (20060101); H04W 52/02 (20090101); H04W
84/12 (20090101) |
Field of
Search: |
;370/311 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Stoianov et al.,, "PIPENET: A Wireless Sensor Network for Pipeline
Monitoring." IPSN '07, Apr. 25-27, 2007. Cambridge, Massachusetts,
U.S.A. cited by applicant .
Lin et al., "Wireless Sensor Network: Water Distribution Monitoring
System," 7th IEEE Radio & Wireless Symposium, Jan. 2008. cited
by applicant .
Sun et al., "MISE-PIPE: Magnetic induction-based wireless sensor
networks for underground pipeline monitoring," Ad Hoc Networks,
2011, 218-227, 9, Elsevier, The Netherlands. cited by applicant
.
Jawhar et al., "A Framework for Pipelineinfrastructure Monitoring
using Wireless Sensor Networks," In Wireless Telecommunications
Symposium 2007, 2007, 1-7, IEEE, US. cited by applicant.
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Primary Examiner: Cheng; Peter
Attorney, Agent or Firm: Pasternack; Sam MIT Technology
Licensing Office
Parent Case Text
This application claims priority to U.S. Provisional Application
Ser. No. 61/918,791 filed on Dec. 20, 2013, the contents of which
are incorporated herein by reference.
Claims
What is claimed is:
1. Wireless communication system for underground pipeline
inspection comprising: a plurality of sensor nodes moved by robots
within the pipeline, each sensor node including a sensor node radio
transceiver; a plurality of spaced apart, above ground relay nodes
deployed along the pipeline, each relay node including a relay node
radio transceiver having a communications range for communication
with the sensor nodes wherein each relay node switches from a low
duty cycle mode to an active state when a sensor node enters the
communications range of said each relay node and then switches back
to the low duty cycle mode when the sensor node moves out of the
communications range of said each relay node; and a remote
monitoring center in communication with the relay nodes, for
receiving information of a leak detected by a sensor node.
2. The system of claim 1 wherein each sensor node further includes
a microcontroller, an accelerometer and a timer.
3. The system of claim 1 wherein the remote monitoring center is in
communication with the plurality of relay nodes through a mobile
communications network.
4. The system of claim 1 wherein the mobile in-pipe sensor nodes
detect the leak through acoustic or pressure effects, conduct
on-board signal processing, and send the extracted leak detection
information to the above ground relay nodes via a low-frequency
radio transceiver, and wherein the selection of the radio frequency
takes into account the data rate, the antenna size, and the signal
attenuation in multiple transmission media, including the in-pipe
water, plastic pipe body, soil, and air.
5. The system of claim 1 wherein the relay nodes send the received
leak detection information from the sensor nodes to the remote
monitoring center using the high-frequency radio transceiver via an
aboveground mobile network.
6. The system of claim 1 wherein the aboveground mobile network can
be a cellular network, a WiFi network, a WiMAX network, or a
satellite network.
7. The system of claim 1 wherein the remote monitoring center sends
control commands to the relay nodes via an above ground mobile
network, and wherein the relay nodes forward the control commands
to the sensor nodes via low-frequency radio transceivers.
8. The system of claim 1 wherein the sensor nodes can also perform
onboard robot control without control commands from the remote
monitoring center.
9. The system of claim 1 for a seamless handover between two
neighboring relay nodes initiated by a current active relay node
comprising: the current active relay node detecting that an RSSI
value decreases to a threshold, and/or the current active relay
node detecting that the distance between the relay node and the
sensor node increases to a threshold; waking a neighboring relay
node up and putting it into active status.
10. The system of claim 1 for a seamless handover between two
neighboring relay nodes initiated by the mobile sensor node
comprising: the sensor node detecting that a RSSI value decreases
to a threshold, and the sensor node detecting that the distance
between the sensor node and the relay node increases to a
threshold; the sensor node sending the relay node a handover
request; the relay node relaying the handover request and beginning
the handover process.
11. The system of claim 1 in which the relay nodes deal with a
sensor node moving at a high speed comprising; the current relay
node waking its neighboring relay node up and putting it into
active status after detecting that a mobile sensor node has
established a communication link with the current relay node; the
remote monitoring center sending an updated duty cycle
configuration to the relay nodes based on the sensor node's moving
speed; and the relay nodes performing onboard duty cycle
configuration based on the sensor node's moving speed.
12. The system of claim 1 wherein an active relay node decides a
sensor node's global position and movement direction comprising:
the relay node telling its global position by an installed GPS
receiver; the relay node determining the pipeline distance between
the relay node and the sensor node by evaluating the received RSSI
values from the sensor node; the relay node determining the moving
direction of the sensor node by checking the received readings from
an accelerometer installed in the sensor node; the relay node
determining more accurate position of the sensor node by combining
the RSSI values, the last handover record, and the outputs of the
accelerometer and the timer from the sensor node; and the relay
node calculating the sensor node's global position by combining the
relay node's global position and the sensor node's location
relative to the relay node.
13. The system of claim 1 wherein a sensor node decides its global
position comprising: the relay node sending its global position
from an installed GPS receiver to the sensor node; the sensor node
determining the pipeline distance between the sensor node and the
relay node by evaluating the received RSSI values from the relay
node; the sensor node determining its more accurate position by
combining the received RSSI values, and the outputs of the
accelerometer and the timer installed in the sensor node; the
sensor node calculating its global position by combining the
received relay node's global position and the sensor node's
location relative to the relay node.
14. The system of claim 1 for reliably and timely delivering the
leak detection information from a sensor node to the remoter
monitoring center comprising: a sensor node performing real-time
onboard data processing and extracting useful information; the
sensor node packetizing the information with error detection and
correction fields, sending out the resulting packets, and waiting
for ACKs from the relay nodes; the sensor node retransmitting the
packet immediately if failing to receive the corresponding ACK; the
sensor node buffering the leak detection information in its memory
if no communication link with any relay node is available, and
sending out the information immediately whenever a communication
link is available.
15. The system of claim 1 for time synchronization between an
in-pipe sensor node and a relay node comprising: a relay node
retrieving a timestamp from the installed GPS receiver, and the
relay node periodically transmitting a time beacon to inform an
in-pipe sensor node of the timestamp.
Description
BACKGROUND OF THE INVENTION
This invention relates to pipeline leakage detection and more
particularly to a wireless communication system for transmitting
leakage information to a remote location.
Water leakage can reach 30% on average of the water transported
across the water distribution networks [1, 2]. Many different
techniques have been developed to detect leaks, either from the
inside [3, 4] or from the outside of pipes [5]. Studies [3] have
shown that compared with outside-of-the-pipe inspection, in-pipe
inspection is much more accurate. In-pipe inspections are less
sensitive to random events and external noise as well as less
subjective to the operator's experience.
Communication functions are extremely important for an in-pipe
inspection system to provide effective leak detection. For accurate
and real-time leak detection, the sensed information needs to be
reliably and timely transmitted to a remote monitoring center. On
the other hand, in-pipe sensor nodes may need to be remotely
controlled by the remote monitoring center, and accurate and timely
delivery of control commands from the remote monitoring center to
the in-pipe sensor nodes also poses a high requirement on the
communication system.
There are several critical challenges on the development of a
communication system for in-pipe inspection. First, traditional
wired communication systems [6] do not work well. Wired systems
have several drawbacks, such as limited scanning range, limited
sensor mobility, and system failure due to wire damage. Second, for
wireless communication systems, signals need to travel through
different media, including water, plastic, soil, and air, to reach
aboveground. Third, the battery-based energy supply of the in-pipe
sensor nodes is limited. Finally, the motion of the in-pipe sensor
nodes results in dynamic communication links and network
connectivity.
In recent years some systems have been developed to provide
wireless data communications for pipeline impaction or underground
infrastructure monitoring. Different technologies have been
explored to enable wireless communication, such as radio
communications, acoustic communications, magnetic induction,
elastodynamic waves, etc.
Some works adopt radio communications to enable information
transmission for in-pipe inspection. Published application number
2005/0145018 describes a method for remote monitoring of a gas
pipeline using wireless sensor networks. Wireless motes and nodes
are deployed to some identified locations in the pipeline by a
robot. Data from sensors are transmitted to some access points by
using radio communications. Wireless transmitters operate inside
the pipe such that the metal pipe acts as waveguide for the
electromagnetic radiation. However this wireless communication
method may not work well with water pipelines due to the high
attenuation of radio waves in water. Also, the work is not focused
on underground scenarios. U.S. Pat. No. 7,607,351 discloses a
pipeline monitoring system with sensors placed along the pipeline.
Each sensor station is equipped with a satellite modem and
satellite antenna to provide near real time bidirectional
communications between the sensor station and the remote monitoring
center. However, sensors are affixed to the outside of the
pipeline, making it difficult to detect small leaks or damage to
the pipeline. There have been some research works on in-pipe
inspection systems using radio communications [4]. However sensors
in those systems are deployed at some fixed check points inside the
pipe, which is unfeasible for performing sensing very close to a
leak.
Some works developed wireless communication systems in the
pipelines using acoustic waves. U.S. Pat. No. 7,423,931 discloses
an acoustic system for communications in pipelines. A transmitter
located in the pipeline communicates with a receiver by emitting
acoustic signal bursts using the pipeline as a wave-guide or
channel. To provide high data rate transmission, a frequency range
of 3-100 kHz is adopted. However, the designers make no explanation
of how to transmit the information from an underground pipeline to
aboveground devices. The authors in [9] also use an acoustic wave
to transmit sensing data in the pipe. However, two of the major
challenges associated with acoustic communication systems are
limited transmission bandwidth and high power consumption. These
drawbacks make acoustic communication systems unsuitable for
monitoring long pipelines with different pipe geometries.
Some works focus on magnetic induction based wireless communication
systems for underground or underwater applications. U.S. Pat. No.
7,831,205 discloses a network of magnetic induction units that is
configured to transmit a signal to or receive a signal from
neighboring units by modulation of a time-varying magnetic field.
Underground or underwater monitoring applications are suggested
with the sensed data relayed in a multi-hop fashion. Some
researchers have also proposed magnetic induction (MI)-based
communications to wirelessly transmit data with the use of coils of
wire wound on the pipelines [10]. However, in view of the short
range of communications between two neighboring magnetic induction
units or coils, it is impossible to perform large-scale deployment
of such units or coils on long underground pipelines.
Some works adopt elastodynamic waves to enable wireless
communications. U.S. Pat. No. 7,602,668 describes down hole sensor
networks using wireless communications. The communication link
between a sensor and a hub in the wellbore is formed by using
elastodynamic waves. However, this wireless communication method is
unsuitable for in-pipe inspection systems due to deployment
challenges.
Thus, there is a need for a wireless communication system for
underground in-pipe monitoring with mobile sensor nodes. Once such
a system is in place, then pipelines can be monitored with a
long-range and long-time operation in an accurate and real-time
way.
SUMMARY OF THE INVENTION
The present invention provides a wireless communication system for
underground pipeline inspection. Sensor nodes inside the pipeline
are mobile and carried by robots. The wireless communication system
disclosed herein includes mobile sensor nodes inside the
underground pipeline, aboveground relay nodes deployed along the
pipeline, a remote monitoring center, and a mobile communication
network from a third-party provider.
The present invention provides a system and methods to enable
bidirectional wireless communications between the underground
in-pipe sensor nodes and the aboveground remote control center. In
one direction, the sensed information can be transmitted from the
sensor nodes to the remote control center. In the other direction,
control commands can be delivered from the control center to the
robots and/or the sensor nodes. The methods include both the
operation steps for establishing communications between the
underground in-pipe sensor nodes and the aboveground relay nodes,
and the operation steps for establishing communications between the
relay nodes and the remoter monitoring center.
Wireless sensor networks are energy-constrained, especially with
underground in-pipe sensor nodes powered by batteries. The present
invention also provides methods and communication protocols to
enable energy-efficient communications and prolong the network
lifetime.
In one aspect, the wireless communication system for underground
pipeline inspection includes a plurality of sensor nodes moved by
robots within the pipeline, each sensor node including a radio
transceiver. A plurality of spaced apart, above ground relay nodes
are deployed along the pipeline, each relay node including a radio
transceiver for communication with the sensor nodes. A remote
monitoring center is provided in communication with the relay nodes
whereby a leak detected by a sensor node is communicated to the
remote monitoring center. In a preferred embodiment, each sensor
node further includes a microcontroller, an accelerometer and a
timer. It is also preferred that the remote monitoring center be in
communication with the plurality of relay nodes through a mobile
communications network.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the disclosed wireless
communication system for underground in-pipe inspection.
FIG. 2 is a schematic illustration showing a low-duty-cycle mode
for the relay nodes according to the invention.
FIG. 3 is a schematic illustration showing that a relay node first
switches from a low-duty-cycle mode to an active state when a
sensor node enters its communication range and then switches back
to the low-duty-cycle mode when the sensor node moves out of its
communication range.
FIG. 4 is a schematic illustration showing that a relay node wakes
its neighboring relay node and initiates a seamless handover when
detecting that a covered sensor node is moving out of its
communication range.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides a wireless communication system for
underground in-pipe inspection. As shown in FIG. 1, a wireless
communication system 10 for underground pipeline inspection
comprises mobile in-pipe sensor node 12, aboveground relay nodes
14, a remote monitoring center 16, and a mobile communication
network 18 from a third-party service provider.
Each sensor node 12 is carried by a robot, and can move back and
forth inside the pipeline. Each sensor node 12 is equipped with
different types of sensors, such as acoustic or pressure sensors to
detect a leak. Each sensor node 12 may include a microcontroller
for robot control and data processing. Each sensor node 12 also may
include a low-frequency radio transceiver for communication with
the relay nodes. Additionally, each sensor node preferably also
includes an accelerometer and a timer to help localize the position
of the sensor node.
The relay nodes 14 are deployed on the soil surface 20 along the
pipeline 22. Each relay node 14 is equipped with a low-frequency
radio transceiver for communications with the sensor nodes 12. Each
relay node 14 also has a modem/transceiver to communicate with the
mobile communication network 18 from a third-party service
provider. For example, if the mobile communication network is a
cellular network, each relay node 14 may be equipped with a General
Packet Radio Service (GPRS) modem, or an Enhanced GPRS (EGPRS)
modem, or a High-Speed Packet Access (HSPA)/Long Term Evolution
(LTE) modem, depending on the cellular network technology and the
data rate requirement. With such a modem, a relay node 14 first
communicates data from the sensor nodes 12 to the base station (BS)
of the cellular network. Then the core network of the cellular
network can send the data to the remote monitoring center 16
through the Internet. In the other direction, the control commands
from the remote monitoring center 16 can be first delivered to the
relay nodes 14 via the Internet and cellular network, and then
reaches to the on-board controller of a sensor node 12 or robot. In
the case where a cellular network is not available, other types of
wireless communication networks can also be adopted, such as a WiFi
network, WiMAX network, and satellite network, to establish
aboveground communications between the relay nodes 14 and the
remote monitoring center 16. For any such type of network, a
corresponding modem/transceiver can be installed at the relay
nodes.
The present invention provides a preferred radio frequency range of
50-900 MHz for the underground wireless communications. In view of
the high attenuation of radio waves in soil and water, the radio
frequency used for the communications between the underground
sensors nodes 12 and the aboveground relay nodes 14 is much lower
than that used in the aboveground mobile network 18. Depending on
the desired tradeoff between signal attenuation and transmission
rate, the radio frequency range used for underground communications
in this invention can be 50-900 MHz.
The present invention provides a method to save the relay nodes' 14
energy. Each in-pipe sensor node 12 switches its communications
with different aboveground relay nodes as it moves in the
underground pipe 22. In other words, the sensor node and the
communicating/active relay node form a temporary cluster. The relay
node 14 acts as the cluster head, and the sensor node 12 is the
cluster member. To save the relay node's energy, the relay node
operates in an active state only when it is communicating with a
sensor node. If the relay node is not communicating with a sensor
node, it operates in a low-duty-cycle mode. As shown in FIG. 2, the
low-duty-cycle mode periodically puts those relay nodes 14 into
sleep state, thereby reducing the idle listening time. In the sleep
state, the radio is completely turned off. As shown in FIG. 3, if a
sensor node 12 passes by a relay node 14, the relay node 14 will
first switch from the low-duty-cycle mode to the active state when
a sensor node 12 enters it communication range, and then switches
back to the low-duty-cycle mode when the sensor node moves out of
its communication range.
The present invention provides a method for a relay node 14 to wake
its neighboring relay node up and initiate a seamless handover when
detecting that the covered sensor node is going to move out of its
communication range, as shown in FIG. 4. The relay node
periodically evaluates the Received Signal Strength Indicator
(RSSI) values of the incoming data packets from the sensor node. If
a relay node 14 realizes that the RSSI values decrease to a
threshold, or that the distance between the sensor node and the
relay node derived from the RSSI values exceeds a threshold, the
relay node will begin to send wake-up messages to the neighboring
relay node in the direction of the sensor node movement. Once the
neighboring relay node wakes up, it will stay in the active state.
Then the current relay node initiates a seamless handover by
sending messages to the neighboring relay node. Once the handover
succeeds and the communications between the sensor node and the
neighboring relay node is established, the current relay node will
go back to the low-duty-cycle mode.
The present invention provides a method for a sensor node to
initiate the handover process. The sensor node 12 evaluates the
Received Signal Strength Indicator (RSSI) values of the incoming
beacon packets or control packets from a relay node 14. If the
sensor node realizes that the RSSI values decrease to a threshold,
or that the distance between the sensor node and the relay node
derived from the RSSI values exceeds a threshold, the sensor node
embeds a handover request in the outgoing data packets. Once the
relay node receives the request, it will send back handover replies
and begin the handover process with its neighboring relay node.
Compared with the handover initialization by a sensor node, one of
the advantages of handover initialization by a relay node is the
reduced handover overhead on the sensor node, thereby saving the
sensor node's energy.
The present invention provides a method for the communication
system to handle high-speed moving sensor nodes 12. The moving
speed of a sensor node places a bound on how rapidly the network 18
must react. If the sensor node moves at a fast speed, the current
relay node may need to wake the neighboring node up in advance so
that the current relay node can have enough time to perform the
handover. In other words, the high mobility of the sensor node
requires that neighboring relay nodes should remain awake or active
earlier. One way is to allow the current relay node to wake its
neighboring relay node up as soon as the sensor node enters the
communication range of the current relay node. In addition, the
moving speed of a sensor node also imposes requirement on the duty
cycle configurations of the relay nodes. Depending on the sensor
node's moving speed, the relay nodes may have multiple duty cycle
configurations. Based on the specific application scenario, the
remote monitoring center can send a new configuration of the duty
cycle to the relay nodes via the mobile network. Alternatively,
onboard duty cycle selection can also be performed in the relay
nodes.
The present invention also provides a method for an active relay
node to decide a sensor node's global position and movement
direction. First, each relay node knows its global position by a
GPS receiver installed in the relay node. Second, the relay node
determines the geographic or pipelines distance between the sensor
node and the relay node by evaluating the RSSI values of incoming
data packets from the sensor node. Each sensor node is equipped
with an accelerometer and a timer. The head field of the data
packets from the sensor node contains the outputs of the
accelerometer and the timer. Based on the received accelerometer
output the relay node can decide the sensor node's moving
direction. By combining the RSSI values, the last handover record,
and the outputs of the accelerometer and the timer, the current
relay node can obtain more accurate location of the sensor node
relative to the relay node, including which side of the relay node
the sensor node is on. With its global position and the sensor
node's distance relative to the relay node, the relay node derives
the global location of the sensor node.
The present invention provides a method for a sensor node to
determine its global position. An active relay node acts as an
anchor or beacon, and periodically sends it global position to the
sensor node. The sensor node determines its geographic information
or pipeline distance relative to the relay node by evaluating the
RSSI values of the incoming beach packets from the relay node. By
combining the analysis of RSSI values with the outputs of its
accelerometer and timer, the sensor node obtains its more accurate
position relative to the relay node. By combing this relative
position with the received global position of the relay node, the
sensor node determines its global position.
The present invention also provides steps to reliably and timely
deliver leak detection information from a sensor node to the remote
monitoring center. All sensed data are continuously stored on board
and can be sent to the remote monitoring center when necessary. The
sensor node performs real-time onboard data processing and extracts
useful information, such as the leak detection results, leak size,
and leak location. Once the information is available, the sensor
node packetizes the information with error detection and correction
fields, sends out the resulting packets, and waits for ACKs from
the relay nodes. If the sensor node fails to receive the ACKs, it
will retransmit the packets immediately. When there is no
established communication link between the sensor node and any
relay node, for example, the sensor node is out of the
communication range of any relay node, the information is buffered
in the memory of the sensor node. Whenever a communication link
becomes available, the sensor node sends out the information
immediately.
The present invention offers a method for time synchronization
between an in-pipe sensor node and a relay node. The relay node
obtains a timestamp from the installed GPS receiver. Each relay
node periodically transmits a time beacon to inform the in-pipe
sensor node of the timestamp.
It is to be understood that the present invention is not limited to
the embodiment described above, but encompasses any and all
embodiments within the scope of the following claims.
The numbers in square brackets refer to the references listed
herein. The contents of all of these are incorporated herein by
reference.
REFERENCES
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Ivan Stoianov, Lama Nachman, Sam Madden, and TimurTokmouline,
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Yan Wu, Ian Wassell, "Wireless Sensor Network: Water Distribution
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[9] George Kokossalalus, Acoustic Data Communication System for
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wireless sensor networks for underground pipeline monitoring," Ad
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Shuaib, "A Framework for PipelineInfrastructure Monitoring using
Wireless Sensor Networks," in Wireless Telecommunications Symposium
2007, Pomona, Calif., USA, April 2007.
* * * * *
References